CVE-2017-5641 is a critical-severity (CVSS 9.8) Deserialization of Untrusted Data vulnerability in org.apache.flex.blazeds:flex-messaging-core. 2 public exploit or proof-of-concept references are indexed, so weaponization risk is real. A fix is available for org.apache.flex.blazeds:flex-messaging-core — see the affected versions and patch details below.
Apache Flex BlazeDS unsafe deserialization
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
org.apache.flex.blazeds:flex-messaging-core☕org.apache.flex.blazeds:flex-messaging-remotingReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
Previous versions of Apache Flex BlazeDS (4.7.2 and earlier) did not restrict which types were allowed for AMF(X) object deserialization by default. During the deserialization process code is executed that for several known types has undesired side-effects. Other, unknown types may also exhibit such behaviors. One vector in the Java standard library exists that allows an attacker to trigger possibly further exploitable Java deserialization of untrusted data. Other known vectors in third party libraries can be used to trigger remote code execution.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.apache.flex.blazeds:flex-messaging-core | all versions | 4.7.3org.apache.flex.blazeds:flex-messaging-core:4.7.3 |
| ☕Maven | org.apache.flex.blazeds:flex-messaging-remoting | all versions | 4.7.3org.apache.flex.blazeds:flex-messaging-remoting:4.7.3 |
Affected Products
flex blazedsapachexp command view advanced editionhpResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.flex.blazeds:flex-messaging-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.apache.flex.blazeds:flex-messaging-core to 4.7.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2017-5641 is resolved across your whole dependency graph.
Workarounds
Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.
Frequently Asked Questions
Is CVE-2017-5641 in your dependencies?
Find it across Maven, including transitive dependencies.